Adding upstream version 3.4.23.upstream/3.4.23upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 486 insertions, 0 deletions

diff --git a/src/smtp/smtp_chat.c b/src/smtp/smtp_chat.c
new file mode 100644
index 0000000..a020ef8
--- /dev/null
+++ b/src/smtp/smtp_chat.c
@@ -0,0 +1,486 @@
+/*++
+/* NAME
+/*	smtp_chat 3
+/* SUMMARY
+/*	SMTP client request/response support
+/* SYNOPSIS
+/*	#include "smtp.h"
+/*
+/*	typedef struct {
+/* .in +4
+/*		int code;	/* SMTP code, not sanitized */
+/*		char *dsn;	/* enhanced status, sanitized */
+/*		char *str;	/* unmodified SMTP reply */
+/*		VSTRING *dsn_buf;
+/*		VSTRING *str_buf;
+/* .in -4
+/*	} SMTP_RESP;
+/*
+/*	void	smtp_chat_cmd(session, format, ...)
+/*	SMTP_SESSION *session;
+/*	const char *format;
+/*
+/*	DICT	*smtp_chat_resp_filter;
+/*
+/*	SMTP_RESP *smtp_chat_resp(session)
+/*	SMTP_SESSION *session;
+/*
+/*	void	smtp_chat_notify(session)
+/*	SMTP_SESSION *session;
+/*
+/*	void	smtp_chat_init(session)
+/*	SMTP_SESSION *session;
+/*
+/*	void	smtp_chat_reset(session)
+/*	SMTP_SESSION *session;
+/* DESCRIPTION
+/*	This module implements SMTP client support for request/reply
+/*	conversations, and maintains a limited SMTP transaction log.
+/*
+/*	smtp_chat_cmd() formats a command and sends it to an SMTP server.
+/*	Optionally, the command is logged.
+/*
+/*	smtp_chat_resp() reads one SMTP server response. It extracts
+/*	the SMTP reply code and enhanced status code from the text,
+/*	and concatenates multi-line responses to one string, using
+/*	a newline as separator.  Optionally, the server response
+/*	is logged.
+/* .IP \(bu
+/*	Postfix never sanitizes the extracted SMTP reply code except
+/*	to ensure that it is a three-digit code. A malformed reply
+/*	results in a null extracted SMTP reply code value.
+/* .IP \(bu
+/*	Postfix always sanitizes the extracted enhanced status code.
+/*	When the server's SMTP status code is 2xx, 4xx or 5xx,
+/*	Postfix requires that the first digit of the server's
+/*	enhanced status code matches the first digit of the server's
+/*	SMTP status code.  In case of a mis-match, or when the
+/*	server specified no status code, the extracted enhanced
+/*	status code is set to 2.0.0, 4.0.0 or 5.0.0 instead.  With
+/*	SMTP reply codes other than 2xx, 4xx or 5xx, the extracted
+/*	enhanced status code is set to a default value of 5.5.0
+/*	(protocol error) for reasons outlined under the next bullet.
+/* .IP \(bu
+/*	Since the SMTP reply code may violate the protocol even
+/*	when it is correctly formatted, Postfix uses the sanitized
+/*	extracted enhanced status code to decide whether an error
+/*	condition is permanent or transient.  This means that the
+/*	caller may have to update the enhanced status code when it
+/*	discovers that a server reply violates the SMTP protocol,
+/*	even though it was correctly formatted. This happens when
+/*	the client and server get out of step due to a broken proxy
+/*	agent.
+/* .PP
+/*	smtp_chat_resp_filter specifies an optional filter to
+/*	transform one server reply line before it is parsed. The
+/*	filter is invoked once for each line of a multi-line reply.
+/*
+/*	smtp_chat_notify() sends a copy of the SMTP transaction log
+/*	to the postmaster for review. The postmaster notice is sent only
+/*	when delivery is possible immediately. It is an error to call
+/*	smtp_chat_notify() when no SMTP transaction log exists.
+/*
+/*	smtp_chat_init() initializes the per-session transaction log.
+/*	This must be done at the beginning of a new SMTP session.
+/*
+/*	smtp_chat_reset() resets the transaction log. This is
+/*	typically done at the beginning or end of an SMTP session,
+/*	or within a session to discard non-error information.
+/* DIAGNOSTICS
+/*	Fatal errors: memory allocation problem, server response exceeds
+/*	configurable limit.
+/*	All other exceptions are handled by long jumps (see smtp_stream(3)).
+/* SEE ALSO
+/*	smtp_stream(3) SMTP session I/O support
+/*	msg(3) generic logging interface
+/* LICENSE
+/* .ad
+/* .fi
+/*	The Secure Mailer license must be distributed with this software.
+/* AUTHOR(S)
+/*	Wietse Venema
+/*	IBM T.J. Watson Research
+/*	P.O. Box 704
+/*	Yorktown Heights, NY 10598, USA
+/*--*/
+
+/* System library. */
+
+#include <sys_defs.h>
+#include <stdlib.h>			/* 44BSD stdarg.h uses abort() */
+#include <stdarg.h>
+#include <ctype.h>
+#include <stdlib.h>
+#include <setjmp.h>
+#include <string.h>
+#include <limits.h>
+
+/* Utility library. */
+
+#include <msg.h>
+#include <vstring.h>
+#include <vstream.h>
+#include <argv.h>
+#include <stringops.h>
+#include <line_wrap.h>
+#include <mymalloc.h>
+
+/* Global library. */
+
+#include <recipient_list.h>
+#include <deliver_request.h>
+#include <smtp_stream.h>
+#include <mail_params.h>
+#include <mail_addr.h>
+#include <post_mail.h>
+#include <mail_error.h>
+#include <dsn_util.h>
+
+/* Application-specific. */
+
+#include "smtp.h"
+
+ /*
+  * Server reply transformations.
+  */
+DICT   *smtp_chat_resp_filter;
+
+/* smtp_chat_init - initialize SMTP transaction log */
+
+void    smtp_chat_init(SMTP_SESSION *session)
+{
+    session->history = 0;
+}
+
+/* smtp_chat_reset - reset SMTP transaction log */
+
+void    smtp_chat_reset(SMTP_SESSION *session)
+{
+    if (session->history) {
+	argv_free(session->history);
+	session->history = 0;
+    }
+}
+
+/* smtp_chat_append - append record to SMTP transaction log */
+
+static void smtp_chat_append(SMTP_SESSION *session, const char *direction,
+			             const char *data)
+{
+    char   *line;
+
+    if (session->history == 0)
+	session->history = argv_alloc(10);
+    line = concatenate(direction, data, (char *) 0);
+    argv_add(session->history, line, (char *) 0);
+    myfree(line);
+}
+
+/* smtp_chat_cmd - send an SMTP command */
+
+void    smtp_chat_cmd(SMTP_SESSION *session, const char *fmt,...)
+{
+    va_list ap;
+
+    /*
+     * Format the command, and update the transaction log.
+     */
+    va_start(ap, fmt);
+    vstring_vsprintf(session->buffer, fmt, ap);
+    va_end(ap);
+    smtp_chat_append(session, "Out: ", STR(session->buffer));
+
+    /*
+     * Optionally log the command first, so we can see in the log what the
+     * program is trying to do.
+     */
+    if (msg_verbose)
+	msg_info("> %s: %s", session->namaddrport, STR(session->buffer));
+
+    /*
+     * Send the command to the SMTP server.
+     */
+    smtp_fputs(STR(session->buffer), LEN(session->buffer), session->stream);
+
+    /*
+     * Force flushing of output does not belong here. It is done in the
+     * smtp_loop() main protocol loop when reading the server response, and
+     * in smtp_helo() when reading the EHLO response after sending the EHLO
+     * command.
+     * 
+     * If we do forced flush here, then we must longjmp() on error, and a
+     * matching "prepare for disaster" error handler must be set up before
+     * every smtp_chat_cmd() call.
+     */
+#if 0
+
+    /*
+     * Flush unsent data to avoid timeouts after slow DNS lookups.
+     */
+    if (time((time_t *) 0) - vstream_ftime(session->stream) > 10)
+	vstream_fflush(session->stream);
+
+    /*
+     * Abort immediately if the connection is broken.
+     */
+    if (vstream_ftimeout(session->stream))
+	vstream_longjmp(session->stream, SMTP_ERR_TIME);
+    if (vstream_ferror(session->stream))
+	vstream_longjmp(session->stream, SMTP_ERR_EOF);
+#endif
+}
+
+/* smtp_chat_resp - read and process SMTP server response */
+
+SMTP_RESP *smtp_chat_resp(SMTP_SESSION *session)
+{
+    static SMTP_RESP rdata;
+    char   *cp;
+    int     last_char;
+    int     three_digs = 0;
+    size_t  len;
+    const char *new_reply;
+    int     chat_append_flag;
+    int     chat_append_skipped = 0;
+
+    /*
+     * Initialize the response data buffer.
+     */
+    if (rdata.str_buf == 0) {
+	rdata.dsn_buf = vstring_alloc(10);
+	rdata.str_buf = vstring_alloc(100);
+    }
+
+    /*
+     * Censor out non-printable characters in server responses. Concatenate
+     * multi-line server responses. Separate the status code from the text.
+     * Leave further parsing up to the application.
+     * 
+     * We can't parse or store input that exceeds var_line_limit, so we just
+     * skip over it to simplify the remainder of the code below.
+     */
+    VSTRING_RESET(rdata.str_buf);
+    for (;;) {
+	last_char = smtp_get(session->buffer, session->stream, var_line_limit,
+			     SMTP_GET_FLAG_SKIP);
+	/* XXX Update the per-line time limit. */
+	printable(STR(session->buffer), '?');
+	if (last_char != '\n')
+	    msg_warn("%s: response longer than %d: %.30s...",
+		session->namaddrport, var_line_limit, STR(session->buffer));
+	if (msg_verbose)
+	    msg_info("< %s: %.100s", session->namaddrport, STR(session->buffer));
+
+	/*
+	 * Defend against a denial of service attack by limiting the amount
+	 * of multi-line text that we are willing to store.
+	 */
+	chat_append_flag = (LEN(rdata.str_buf) < var_line_limit);
+	if (chat_append_flag)
+	    smtp_chat_append(session, "In:  ", STR(session->buffer));
+	else {
+	    if (chat_append_skipped == 0)
+		msg_warn("%s: multi-line response longer than %d %.30s...",
+		  session->namaddrport, var_line_limit, STR(rdata.str_buf));
+	    if (chat_append_skipped < INT_MAX)
+		chat_append_skipped++;
+	}
+
+	/*
+	 * Server reply substitution, for fault-injection testing, or for
+	 * working around broken systems. Use with care.
+	 */
+	if (smtp_chat_resp_filter != 0) {
+	    new_reply = dict_get(smtp_chat_resp_filter, STR(session->buffer));
+	    if (new_reply != 0) {
+		msg_info("%s: replacing server reply \"%s\" with \"%s\"",
+		     session->namaddrport, STR(session->buffer), new_reply);
+		vstring_strcpy(session->buffer, new_reply);
+		if (chat_append_flag) {
+		    smtp_chat_append(session, "Replaced-by: ", "");
+		    smtp_chat_append(session, "     ", new_reply);
+		}
+	    } else if (smtp_chat_resp_filter->error != 0) {
+		msg_warn("%s: table %s:%s lookup error for %s",
+			 session->state->request->queue_id,
+			 smtp_chat_resp_filter->type,
+			 smtp_chat_resp_filter->name,
+			 printable(STR(session->buffer), '?'));
+		vstream_longjmp(session->stream, SMTP_ERR_DATA);
+	    }
+	}
+	if (chat_append_flag) {
+	    if (LEN(rdata.str_buf))
+		VSTRING_ADDCH(rdata.str_buf, '\n');
+	    vstring_strcat(rdata.str_buf, STR(session->buffer));
+	}
+
+	/*
+	 * Parse into code and text. Do not ignore garbage (see below).
+	 */
+	for (cp = STR(session->buffer); *cp && ISDIGIT(*cp); cp++)
+	     /* void */ ;
+	if ((three_digs = (cp - STR(session->buffer) == 3)) != 0) {
+	    if (*cp == '-')
+		continue;
+	    if (*cp == ' ' || *cp == 0)
+		break;
+	}
+
+	/*
+	 * XXX Do not simply ignore garbage in the server reply when ESMTP
+	 * command pipelining is turned on.  For example, after sending
+	 * ".<CR><LF>QUIT<CR><LF>" and receiving garbage followed by a
+	 * legitimate 2XX reply, Postfix recognizes the server's QUIT reply
+	 * as the END-OF-DATA reply after garbage, causing mail to be lost.
+	 * 
+	 * Without the ability to store per-domain status information in queue
+	 * files, automatic workarounds are problematic:
+	 * 
+	 * - Automatically deferring delivery creates a "repeated delivery"
+	 * problem when garbage arrives after the DATA stage. Without the
+	 * workaround, Postfix delivers only once.
+	 * 
+	 * - Automatically deferring delivery creates a "no delivery" problem
+	 * when the garbage arrives before the DATA stage. Without the
+	 * workaround, mail might still get through.
+	 * 
+	 * - Automatically turning off pipelining for delayed mail affects
+	 * deliveries to correctly implemented servers, and may also affect
+	 * delivery of large mailing lists.
+	 * 
+	 * So we leave the decision with the administrator, but we don't force
+	 * them to take action, like we would with automatic deferral.  If
+	 * loss of mail is not acceptable then they can turn off pipelining
+	 * for specific sites, or they can turn off pipelining globally when
+	 * they find that there are just too many broken sites.
+	 */
+	session->error_mask |= MAIL_ERROR_PROTOCOL;
+	if (session->features & SMTP_FEATURE_PIPELINING) {
+	    msg_warn("%s: non-%s response from %s: %.100s",
+		     session->state->request->queue_id,
+		     smtp_mode ? "ESMTP" : "LMTP",
+		     session->namaddrport, STR(session->buffer));
+	    if (var_helpful_warnings)
+		msg_warn("to prevent loss of mail, turn off command pipelining "
+			 "for %s with the %s parameter",
+			 STR(session->iterator->addr),
+			 VAR_LMTP_SMTP(EHLO_DIS_MAPS));
+	}
+    }
+
+    /*
+     * Extract RFC 821 reply code and RFC 2034 detail. Use a default detail
+     * code if none was given.
+     * 
+     * Ignore out-of-protocol enhanced status codes: codes that accompany 3XX
+     * replies, or codes whose initial digit is out of sync with the reply
+     * code.
+     * 
+     * XXX Potential stability problem. In order to save memory, the queue
+     * manager stores DSNs in a compact manner:
+     * 
+     * - empty strings are represented by null pointers,
+     * 
+     * - the status and reason are required to be non-empty.
+     * 
+     * Other Postfix daemons inherit this behavior, because they use the same
+     * DSN support code. This means that everything that receives DSNs must
+     * cope with null pointers for the optional DSN attributes, and that
+     * everything that provides DSN information must provide a non-empty
+     * status and reason, otherwise the DSN support code wil panic().
+     * 
+     * Thus, when the remote server sends a malformed reply (or 3XX out of
+     * context) we should not panic() in DSN_COPY() just because we don't
+     * have a status. Robustness suggests that we supply a status here, and
+     * that we leave it up to the down-stream code to override the
+     * server-supplied status in case of an error we can't detect here, such
+     * as an out-of-order server reply.
+     */
+    VSTRING_TERMINATE(rdata.str_buf);
+    vstring_strcpy(rdata.dsn_buf, "5.5.0");	/* SAFETY! protocol error */
+    if (three_digs != 0) {
+	rdata.code = atoi(STR(session->buffer));
+	if (strchr("245", STR(session->buffer)[0]) != 0) {
+	    for (cp = STR(session->buffer) + 4; *cp == ' '; cp++)
+		 /* void */ ;
+	    if ((len = dsn_valid(cp)) > 0 && *cp == *STR(session->buffer)) {
+		vstring_strncpy(rdata.dsn_buf, cp, len);
+	    } else {
+		vstring_strcpy(rdata.dsn_buf, "0.0.0");
+		STR(rdata.dsn_buf)[0] = STR(session->buffer)[0];
+	    }
+	}
+    } else {
+	rdata.code = 0;
+    }
+    rdata.dsn = STR(rdata.dsn_buf);
+    rdata.str = STR(rdata.str_buf);
+    return (&rdata);
+}
+
+/* print_line - line_wrap callback */
+
+static void print_line(const char *str, int len, int indent, void *context)
+{
+    VSTREAM *notice = (VSTREAM *) context;
+
+    post_mail_fprintf(notice, " %*s%.*s", indent, "", len, str);
+}
+
+/* smtp_chat_notify - notify postmaster */
+
+void    smtp_chat_notify(SMTP_SESSION *session)
+{
+    const char *myname = "smtp_chat_notify";
+    VSTREAM *notice;
+    char  **cpp;
+
+    /*
+     * Sanity checks.
+     */
+    if (session->history == 0)
+	msg_panic("%s: no conversation history", myname);
+    if (msg_verbose)
+	msg_info("%s: notify postmaster", myname);
+
+    /*
+     * Construct a message for the postmaster, explaining what this is all
+     * about. This is junk mail: don't send it when the mail posting service
+     * is unavailable, and use the double bounce sender address, to prevent
+     * mail bounce wars. Always prepend one space to message content that we
+     * generate from untrusted data.
+     */
+#define NULL_TRACE_FLAGS	0
+#define NO_QUEUE_ID		((VSTRING *) 0)
+#define LENGTH	78
+#define INDENT	4
+
+    notice = post_mail_fopen_nowait(mail_addr_double_bounce(),
+				    var_error_rcpt,
+				    MAIL_SRC_MASK_NOTIFY, NULL_TRACE_FLAGS,
+				    SMTPUTF8_FLAG_NONE, NO_QUEUE_ID);
+    if (notice == 0) {
+	msg_warn("postmaster notify: %m");
+	return;
+    }
+    post_mail_fprintf(notice, "From: %s (Mail Delivery System)",
+		      mail_addr_mail_daemon());
+    post_mail_fprintf(notice, "To: %s (Postmaster)", var_error_rcpt);
+    post_mail_fprintf(notice, "Subject: %s %s client: errors from %s",
+		      var_mail_name, smtp_mode ? "SMTP" : "LMTP",
+		      session->namaddrport);
+    post_mail_fputs(notice, "");
+    post_mail_fprintf(notice, "Unexpected response from %s.",
+		      session->namaddrport);
+    post_mail_fputs(notice, "");
+    post_mail_fputs(notice, "Transcript of session follows.");
+    post_mail_fputs(notice, "");
+    argv_terminate(session->history);
+    for (cpp = session->history->argv; *cpp; cpp++)
+	line_wrap(printable(*cpp, '?'), LENGTH, INDENT, print_line,
+		  (void *) notice);
+    post_mail_fputs(notice, "");
+    post_mail_fprintf(notice, "For other details, see the local mail logfile");
+    (void) post_mail_fclose(notice);
+}